It manages DRM-free ebooks, including conversions between formats. It has its own forum here. If you have Calibre installed, then the command any2mobi will convert many ebook formats into MOBI. In this case I converted a MOBI into another MOBI, but because Calibre re-analyses the ebook much of the original metadata (including the clipping limit) is lost in the conversion. Note that any2mobi only works on DRM-free ebooks so you need to use mobidedrm first, which I why I suggested the command line program (any2mobi) from Calibre rather than its GUI. If you know how to use mobidedrm, any2mobi is very similar.